Lab experiments on a new strain of the H7N9 bird flu suggest the virus can pass easily among animals and can cause lethal disease, raising alarms that it has the potential to create a global human pandemic.
The H7N9 virus has been circulating in China since 2013, causing severe disease in people exposed to infected poultry. Last year, human cases spiked, and the virus split into two distinct strains that are so different they no longer can be treated with existing vaccines.
One of these has also become highly pathogenic, meaning it has gained the ability to kill birds, posing a threat to agriculture markets.
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